Honestly I think this is a way to indirectly nerf the job since as it stands, after the smn nerf, it's the higher rdps caster by a not insignificant margin, at least according to fflogs data. The lower vit won't be a problem: -5 vit points won't kill you and BLM is the only caster with a self defensive skill that can be effectively and easily used during an enounter. So at the end of the day, it's just a very slight relative damage nerf to bring it closer to the other two casters I suppose. The devs probably thought it was the best way to do it. I agree that the amount of tomestones you have to spend for the sps bis is a bit excessive though.